support the full range of type modifiers when declaring concept vars and testing proc signatures

compiler/parampatterns.nim

@@ -235,6 +235,13 @@ proc isAssignable*(owner: PSym, n: PNode; isUnsafeAddr=false): TAssignableResult
   of nkStmtList, nkStmtListExpr:
     if n.typ != nil:
       result = isAssignable(owner, n.lastSon, isUnsafeAddr)
+  of nkVarTy:
+    # XXX: The fact that this is here is a bit of a hack.
+    # The goal is to allow the use of checks such as "foo(var T)"
+    # within concepts. Semantically, it's not correct to say that
+    # nkVarTy denotes an lvalue, but the example above is the only
+    # possible code which will get us here
+    result = arLValue
   else:
     discard
 

compiler/parser.nim

@@ -1793,8 +1793,16 @@ proc parseObject(p: var TParser): PNode =
   addSon(result, parseObjectPart(p))
 
 proc parseTypeClassParam(p: var TParser): PNode =
-  if p.tok.tokType in {tkOut, tkVar}:
-    result = newNodeP(nkVarTy, p)
+  let modifier = case p.tok.tokType
+    of tkOut, tkVar: nkVarTy
+    of tkPtr: nkPtrTy
+    of tkRef: nkRefTy
+    of tkStatic: nkStaticTy
+    of tkType: nkTypeOfExpr
+    else: nkEmpty
+
+  if modifier != nkEmpty:
+    result = newNodeP(modifier, p)
     getTok(p)
     result.addSon(p.parseSymbol)
   else:

compiler/semdata.nim

@@ -230,6 +230,17 @@ proc makePtrType*(c: PContext, baseType: PType): PType =
   result = newTypeS(tyPtr, c)
   addSonSkipIntLit(result, baseType.assertNotNil)
 
+proc makeTypeWithModifier*(c: PContext,
+                           modifier: TTypeKind,
+                           baseType: PType): PType =
+  assert modifier in {tyVar, tyPtr, tyRef, tyStatic, tyTypeDesc}
+
+  if modifier in {tyVar, tyTypeDesc} and baseType.kind == modifier:
+    result = baseType
+  else:
+    result = newTypeS(modifier, c)
+    addSonSkipIntLit(result, baseType.assertNotNil)
+
 proc makeVarType*(c: PContext, baseType: PType): PType =
   if baseType.kind == tyVar:
     result = baseType
@@ -238,8 +249,11 @@ proc makeVarType*(c: PContext, baseType: PType): PType =
     addSonSkipIntLit(result, baseType.assertNotNil)
 
 proc makeTypeDesc*(c: PContext, typ: PType): PType =
-  result = newTypeS(tyTypeDesc, c)
-  result.addSonSkipIntLit(typ.assertNotNil)
+  if typ.kind == tyTypeDesc:
+    result = typ
+  else:
+    result = newTypeS(tyTypeDesc, c)
+    result.addSonSkipIntLit(typ.assertNotNil)
 
 proc makeTypeSymNode*(c: PContext, typ: PType, info: TLineInfo): PNode =
   let typedesc = makeTypeDesc(c, typ)

compiler/semtypes.nim

@@ -135,7 +135,7 @@ proc semAnyRef(c: PContext; n: PNode; kind: TTypeKind; prev: PType): PType =
     let isCall = ord(n.kind in nkCallKinds+{nkBracketExpr})
     let n = if n[0].kind == nkBracket: n[0] else: n
     checkMinSonsLen(n, 1)
-    var base = semTypeNode(c, n.lastSon, nil)
+    var base = semTypeNode(c, n.lastSon, nil).skipTypes({tyTypeDesc})
     result = newOrPrevType(kind, prev, c)
     var isNilable = false
     # check every except the last is an object:
@@ -155,7 +155,7 @@ proc semAnyRef(c: PContext; n: PNode; kind: TTypeKind; prev: PType): PType =
 proc semVarType(c: PContext, n: PNode, prev: PType): PType =
   if sonsLen(n) == 1:
     result = newOrPrevType(tyVar, prev, c)
-    var base = semTypeNode(c, n.sons[0], nil)
+    var base = semTypeNode(c, n.sons[0], nil).skipTypes({tyTypeDesc})
     if base.kind == tyVar:
       localError(n.info, errVarVarTypeNotAllowed)
       base = base.sons[0]
@@ -1404,7 +1404,7 @@ proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
   of nkDistinctTy: result = semDistinct(c, n, prev)
   of nkStaticTy:
     result = newOrPrevType(tyStatic, prev, c)
-    var base = semTypeNode(c, n.sons[0], nil)
+    var base = semTypeNode(c, n.sons[0], nil).skipTypes({tyTypeDesc})
     result.rawAddSon(base)
     result.flags.incl tfHasStatic
   of nkIteratorTy:

compiler/sigmatch.nim

@@ -622,17 +622,27 @@ proc matchUserTypeClass*(c: PContext, m: var TCandidate,
       dummyName: PNode
       dummyType: PType
 
-    if param.kind == nkVarTy:
+    let modifier = case param.kind
+      of nkVarTy: tyVar
+      of nkRefTy: tyRef
+      of nkPtrTy: tyPtr
+      of nkStaticTy: tyStatic
+      of nkTypeOfExpr: tyTypeDesc
+      else: tyNone
+
+    if modifier != tyNone:
       dummyName = param[0]
-      dummyType = if a.kind != tyVar: makeVarType(c, a) else: a
+      dummyType = c.makeTypeWithModifier(modifier, a)
     else:
       dummyName = param
       dummyType = a
 
     internalAssert dummyName.kind == nkIdent
-    var dummyParam = newSym(skVar, dummyName.ident, body.sym, body.sym.info)
+    var dummyParam = newSym(if modifier == tyTypeDesc: skType else: skVar,
+                            dummyName.ident, body.sym, body.sym.info)
     dummyParam.typ = dummyType
     addDecl(c, dummyParam)
+
     #echo "B ", dummyName.ident.s, " ", typeToString(dummyType), " ", dummyparam.kind
 
   var checkedBody = c.semTryExpr(c, body.n[3].copyTree)
@@ -1411,12 +1421,12 @@ proc inferTypeClassParam*(m: var TCandidate, f, a: PType): bool =
   if inferrableType == nil: return false
 
   var inferAs = f
-  
+
   case f.kind
   of tyGenericParam:
     var prev  = PType(idTableGet(m.bindings, f))
     if prev != nil: inferAs = prev
-  
+
   of tyFromExpr:
     let computedType = tryResolvingStaticExpr(m, f.n).typ
     case computedType.kind
@@ -1426,10 +1436,10 @@ proc inferTypeClassParam*(m: var TCandidate, f, a: PType): bool =
       inferAs = computedType
     else:
       localError(f.n.info, errTypeExpected)
-  
+
   else:
     discard
-    
+
   inferrableType.assignType inferAs
   return true
 
@@ -1470,7 +1480,8 @@ proc paramTypesMatchAux(m: var TCandidate, f, argType: PType,
         argType = arg.typ
 
   var
-    useTypeLoweringRuleInTypeClass = c.inTypeClass > 0 and
+    useTypeLoweringRuleInTypeClass = argType != nil and
+                                     c.inTypeClass > 0 and
                                      not m.isNoCall and
                                      f.kind != tyTypeDesc
 
@@ -1478,9 +1489,9 @@ proc paramTypesMatchAux(m: var TCandidate, f, argType: PType,
           argType.skipTypes({tyTypeDesc, tyFieldAccessor})
         else:
           argType
-    
+
     r = typeRel(m, f, a)
-  
+
   if r != isNone and m.calleeSym != nil and
      m.calleeSym.kind in {skMacro, skTemplate}:
     # XXX: duplicating this is ugly, but we cannot (!) move this